Conventionally, a small-size module (hereinafter simply referred to as a “module”) which is connected with a terminal such as a mobile terminal, which is represented by a smartphone, to perform data communication using, for example, a short-range wireless communication means such as Bluetooth (registered trademark) and NFC is known. The module is connected to be able to communicate with the terminal and therefore provides a user with various functions (for example, a function such as mobile network communication) via the terminal.
In the following Patent Literature 1, a client-server system in which a server and one or more clients are connected using Bluetooth (registered trademark) and mutually perform information communication is disclosed. In this client-server system, the server forcibly disconnects the connection of the currently connected client if clients of a number capable of being simultaneously connected are already connected when a new client is connected.